Chlorodifluoroamine and a process for its preparation



3,101,997 CEEORODEFLUOROAMINE AND A PROCESS FOR ITS PREPARATION Jeremiah P. Freeman and Robert C. Petry, Huntsvilie,

Ala, assiwors to R'ohm & Haas Company, Philadelphia, Pa., a corporation of Delaware No Drawing. Filed Oct. 14, 1960, Ser. No. 62,561

3 Claims. (Cl. 23-14) Thisinven-tion concerns chlorodifluoroarnine, CIN F and processes for the preparation thereof. This application is a continuation-in-part of Serial No. 28,024, filed May 10, 196(l, expressly abandoned on November 30, 1960 A previously known fluorine compound, difluoroamine, HNF is used in the preparation of this new compound, chlorodifiuoroamine. HNF may be prepared by the processes set forth in Kennedy et al. JACS 81, 2906 (i959), and Lawton et al. JAOS 81, 4755 (1959). Chlorodifiuoroamine is prepared by the reaction of difluoroarnine with boron trichloride (BCl Another previously known compound, tetrafiuorohydrazine, N F can be used as starting material tor the preparation of chlorodifluoroamine. N F can be prepared by the process shown in Coiburn et al. IACS 80, 5004 (1958). ClNF can be prepared by reacting N F with chlorine or iodine monochloride.

Chlorodifiuoroamine, because of its high order of reactiuity, is a valuable intermediate for the preparation of a variety of chemicals.

Although ClNF can be prepared from. N F it can also be used to prepare N F Thus, ClNF reacts with mercury to form N F and mercurous chloride. ClNF also reacts with divinyl mercury (H-g(CH=CH to form N F and vinyl chloride. The use for vinyl chloride is well known to those skilled in the art. Polymers and copolymers of vinyl chloride are used in a wide variety of applications.

Chlorodifluoroamine also finds utility as an oxidizing agent and also as a bleaching agent for materials such as textiles.

One process for producing ClNF is the reaction of HNF with BCl Whereas the molar ratios of HNF to BCl can be varied from 2 to 1 to l to 2, the preferred molar ratio of reactants is 1 to l.

The reaction proceeds rapidly at low temperatures and the reaction temperature may be varied over the range from about --35 C. to about 25 C. A preferred method of preparation, comprises distilling equimolar quantities of BCl and H NF into a reaction vessel at a temperature of irom about --l30 C. to about -l96 C. and allowing the reaction mixture to warm to room temperature, i.e., about 20 to 30 C, The ClNF fraction can then be isolated by distilling the volatile products through a series of traps, the temperatures of which are maintained such that the ClNF fraction is separated from less volatile contaminants. The clNF -containing traction can be further purified by passage of the inaction through a tower packed with an alkaline material, such as sodium hydroxide or potassium hydroxide, preferably supported on an inert material such as kieseltguhr, asbestos, etc. This step is then followed by passage of the gas through a low temperature trap to remove water. An alternate way of.

. United States Patent system. The equilibrium concentration of CINE, is given by the equation: z)=[ 2 4)( 21 Study of the equilibrium constant in the temperature range from 29 to 83 C. has given the following equation for the temperature dependence on the equilibrium constant:

2 log K: f +5.77

When utilized as a preparative method, the yield of C1NF is dependent on the temperature and molar ratios of C1 to N F as defined by Equations 1 and 2. An increase in temperature and increase in the C1 to N F ratio, increases the conversion to CINF The upper temperature limit is that at which CINF or N F attacks the reaction vessel to give decomposition products. In Pyrex apparatus, this temperature is about 150 C. The irradiation time required to reach equilibrium is dependent on the intensity of the light source and the pressure of the reactants. In the equilibrium studies which were made, irradiation times of 10-15 minutes were sufiicient to reach equilibrium using a Hanovia EH-4 lamp as the light source and reactant pressures in the neighborhood of 600 mm. in 100cc. Pyrex reaction bulbs. Separation of ClNF from unreacted N F and C1 can be accomplished by an eflicient low temperature fractionating column or by the application of gas chromatography. Whereas some ClNF is obtained when the molar ratio of N F to C1 is l to 1, high excesses of C1 up to a molar ratio of l N F to 100 C1 are preferred.

Iodine monochloride can be substituted for chlorine in the above reaction. The molar ratios of iodine monochloride to N F can be varied from 1.5 to 1 to about to 1. Using iodine monochlor-ide with NgF the irradiation period should be 2 to 4 hours depending on the reaction temperature. At room temperature, an irradiation period of three hours is satisfactory.

on a Consolidated Electrodynamics Model 620 Mass Spectrometer.

Fragmentation Pattern of CINF;

The peaks attributed to Cl may arise from partial disproportionation of the sample to C1 and N F in the metal inlet system of the mass spectrometer. Samples giving essentially the same cracking pattern were shown to contain less than 0.5% C1 by U.V. spectrometry.

A molecular weight determination of ClNF :by the vapor density method gave the theoretical value of 87.5 within experimental error. Two determinations gave measured values of 87.5 and 87.8.

Vapor Pressure The vapor pressure curve for ClNF was measured and can be expressed by the equation The extrapolated boiling point was found to be 67 C. The heat of vaporization calculated from the above equation is 4350 caL/mole with a Trouton constant of 21.0.

Vapor pressures were measured with the aid of a spoon gauge operated as a null instrument by balancing against a mercury manometer. Temperatures were measured with a calibrated copper-constantan thermocouple.

The melting point of ClNF' was not obtained but lies between -183 C. and -196 C.

The infrared spectrum of ClNF consists of very strong bands centered at 10.8 (triplet), 11.7 (doublet) and 144;]. (triplet); a doublet of medium intensity centered at 13.4;1. and weak bands at 5.4, 5.7, 5.9 and 7.3 Since N F exhibits a very strong absorption band at 9.9,u. the presence of this material as impurity in ClNF is readily detectable.

REACTIONS OF CHLORODIFLUOROAMINE Reaction of ClNF With Mercury Mercury and ClNF were shown to react according to the following equation:

A sample of ClNF (1.26 10* mole), previously shown to contain 0.5% C1 by UV. absorption, was stirred with excess mercury in a Pyrex reaction vessel at room temperature for 2 hours. The recovered volatile material amounted to 0.63 10 mole. Mass spectral analysis showed 95% N F and 4% N F and 1% SiF The N F and SiF were byproducts of the reaction since the starting ClNF showed neither N 1 nor SiF by mass spectral analysis. The non-Volatile residue from the reaction was found to be Hg Cl containing a trace of HgFz.

Reaction of ClNF With Divinyl Mercury The reaction of divinyl mercury 1 with ClNF has been found to proceed essentially as follows:

A 100 cc. Pyrex reaction vessel equipped with stopcock, magnetic stirrer and a mercury manometer (pro tected with a layer of KelF oil) was changed in vacuo with 4.0 g. (1.6 10 mole) divinyl mercury and 2.5 X 10- mole ClNF The reaction mixture was stirred at C. for 3 hours after which time there was no further pressure decrease. The reaction mixture was fractionated in vacuo through traps maintained at 80, and 196 C. The -19'6 fraction amounted to 2.4 mole. Analysis of the fraction by mass and infrared spectrometry showed a mixture of N F and vinyl chloride in approximately equal amount. The -80 C. fraction con- B. Bartocha. and F. G. A. Stone, Z, Naturforschg.

tained the excess divinyl mercury. The non-volatile solid residue in the reaction bulb was found to be CH =CHHgCl with a small amount of Hg. Both the N F and vinyl chloride yield in this reaction (based on the above equation) were approximately The following examples set forth certain well-defined embodiments of the application of this invention. They are not, however, to be considered as limitations thereof, since many modifications may be made without departing from the spirit and scope of this invention.

Unless otherwise specified, all parts are parts by weight. All temperatures are centigrade unless otherwise noted.

EXAMPLE I HNF -BCl Reaction A l-liter Pyrex reaction bulb equipped with stopcock and condensing arm was charged in vacuo with 1.40 X 10- mole each of boron trichloride and difiuoroamine. The reactants were distilled into the reaction bulb with the condensing arm maintained at approximately -l30 C. (methyl cyclohexane slush both temperature). The cooling bath was removed and the reaction mixture allowed to warm to ambient temperature. Reaction occurred below room temperature during the warm-up period and the bulb became coated with white solid. The pressure in the reaction bulb corresponded to 2.0x 10 mole gaseous material at the completion of the reaction. Mass spectral and infrared analysis of the gaseous material showed the presence of CINF HCl, and C1 with small amounts of BCl and BF;,. The solid non-volatile reaction product was not identified. The gaseous reaction mixture was separated by low temperature vacuum fractionation through traps maintained at --140 and 196 C. The --l96 fraction contained the ClNF contaminated with HCl and small amounts of C1 and BF Purification was accomplished by passage of this fraction through an as-carite (sodium hydroxide on an asbestos carrier) packed tower at 0 C. and low pressure, followed by fractionation through a. trap maintained at '130 C. to remove water. The passed fraction collected at --196 C. amounted to 6.96 10- mole (49.8% yield) and was essentially pure ClNF Calculated for ClNF Cl, 40.54%; F, 43.45% Found: Cl, 39.92%; F, 42.85%.

An alternate purification method consists of exposing the ClNF fraction to 3 N sodium hydroxide solution (at room temperature) with stirring for 30 minutes, followed by fractionation through a trap at 130 C. to remove water.

EXAMPLE H N F -Cl Reaction A cc. Pyrex reaction bulb containing 50 mm. N E; and 456 mm. C1 was thermostated in a constant temperature water-bath at 83.10 C. and irradiated with a Hanovia EH-4 lamp for 15 minutes at which time equilibrium had been established. Analysis of the reaction mixture by quantitative infrared spectrometry showed the presence of 22.0 mm. ClNF and 39.0 mm. N F Separation of the ClNTF from the unreacted C1 and N F was accomplished by gas chromatography on a silica gel column at -45 C. The ClNF peak was trapped out of the efiiuent helium stream in a trap at -196 C.

EXAMPLE HI N F ICI Reaction A 500 cc. Pyrex reaction bulb, changed in vacuo with 6X 10-3 mole 101 and 4.3 x10 mole N F was irradiated at room temperautre with a Ha-novia EH-4 lamp for 3 hours. Work-up of the reaction mixture by fractionation through traps at -80 and -196 C. and infrared analysis of the 19'6 C. fraction indicated the information of approximately 1 10- mole CINF Subsequent 6 irradiation of the reaction mixtrlre for 12 hours produced References Cited in the file of this patent iietztllshjiditional C1NF indicating equilibrium had been UNITED STATES PATENTS We i r 2,736,694 Gunning Feb. 28, 1956 1. Chlorodifiuoroamine, OlNF- 5 2,950,954 Mailer e 30, 1960' 2. A process for the preparation of chlorod ifluoroamine 237L820 Rolmgsou 14, 1961 which comprises reacting difiuoroarnine with lboron tri- 2,987,456 Lauer J1me 1961 chloride at a temperature of from about 35 C. to about 25 C. and recovering the chlorodifluoroamine so formed. OTHER REFERENCES 3. Aprocess as set forth in claim 2 in whioh the molar 10 Petry: J. American Chem. 800., 82, #9, pp. 2400, ratio of difluoroamine to boron trichloride is 1 to 1. 2401, May 5, 1960. 

1. CHLORODIFLUOROAMINE, CINF2.
 2. A PROCESS FOR THE PREPARATION OF CHLORODIFLUOROAMINE WHICH COMPRISES REACTING DIFLUOROAMINE WITH BORON TRICHLORIDE AT A TEMPERATURE OF FROM ABOUT -35*C. TO ABOUT 25*C. AND RECOVERING THE CHLOROFLUOROAMINE SO FORMED. 